Comparing Polarimetric and Spectral Retrievals of Cloud Properties: Lessons from LES cloud satellite simulator studies

A remote sensing cloud retrieval simulator, created by coupling an LES cloud model with vector radiative transfer (RT) models is the ideal framework for assessing cloud remote sensing techniques. This simulator serves as a tool for understanding spectral/polarimetric retrievals by comparing them directly to LES cloud properties (retrieval closure) and for comparing different retrieval techniques (spectral/polarimetric intercomparison) to one another. With future remote sensing missions like NASA’s Aerosols/Clouds/Ecosystems (ACE) planning to feature advanced polarimetric instruments it is important to understand how these techniques compare to one another. The cloud retrieval simulator we’ve developed allows us to probe these important questions in a realistically relevant test bed. Our simulator utilizes the output from the DHARMA LES [Ackerman et al., 2004] with cloud properties based on the clouds observed during the DYCOMS-II and ATEX field campaigns. Vector RT generated by polarized doubling adding and monte carlo models (PDA, MCPOL). Polarized retrievals were performed utilizing a method similar to those used for instruments such as POLDER [Bréon & Doutriaux-Boucher, 2005] and spectral retrievals were performed using a method similar to MODIS [Nakajima & King, 1990].